1. Field Of The Invention
The present invention relates to valves, and more particularly, to a valve assembly that selectively attaches to a fluid-filled pipe to provide access to the fluid contained within the pipe.
2. Description Of The Related Art
Self-piercing valves sometimes referred to as "saddle valves" or self-tapping valves, are used to supply a fluid from a fluid-filled pipe at a location where a standard valve or other access has not been installed on the pipe. A self-piercing valve normally has an upper and lower member which are fitted about the pipe, and then the upper and lower members are fastened together to frictionally hold the pipe. Once held within the valve, a needle extending means is normally actuated to selectively extend a needle to puncture the pipe, thus providing access to the fluid contained within the pipe.
One known type of self-piercing valve has a hollow needle with a large diameter such that when the needle pierces the fluid-filled pipe, fluid flows from the pipe through the hollow interior of the needle into a passage within the upper member and to an outlet on the upper member self-piercing valve. With that self-piercing valve, the needle remains protruding into the pipe throughout its use period and, among other functions, the protruding needle assists in preventing relative angular rotation between the pipe and the valve.
Another known type of self-piercing valve uses a solid needle to pierce the pipe, which needle is retracted after puncture so that fluid flows from the pipe through the body of the valve. Upon retraction of the needle, the valve can spin about the pipe thereby causing the puncture site to leak.
To assist in prevention of relative rotation between the valve and the pipe, prior art self-piercing valves are typically provided with a set screw which is threaded normally through one of the fastening members to engage the pipe. Among some of the problems experienced by use of the set screw are: over tightening (including puncturing); and minimal surface contact between the set screw tip and pipe surface (such that the grip can easily weaken and slip over time).
Thus, there exists a need for an improved self-piercing valve assembly and method for mounting the valve to its host pipe.